Governmental agencies (e.g., the Environmental Protection Agency) have enacted regulations to limit the amount of evaporative emissions emitted by boats and other marine crafts during operation and/or non-operation of the marine vehicle. More specifically, government regulations (e.g., title 40 of the Code of Federal Regulations) have been enacted toward controlling diurnal evaporative emissions of marine vehicles. In particular, these regulations limit the amount of evaporative diurnal emissions that a marine vehicle may permissibly emit during a diurnal cycle (e.g., periods of non-operation).
During non-operation of the marine vehicle, for example, a fuel delivery system of a marine vehicle may be subjected to daily ambient temperature changes that may cause the release of hydrocarbons to the environment. Such emissions are commonly referred to as diurnal emissions and are considered hazardous to the environment. Often, fuel or vapor leakage is exacerbated by diurnal temperature cycles. Diurnal emissions are evaporative emissions that are released due to the daily cycle of liquid fuel becoming fuel vapor during the daylight hours and condensing during the night. More specifically, during a diurnal cycle, the temperature of the air decreases during the night hours, causing the pressure of the fuel and/or fuel vapors in the fuel tank to decrease. When the pressure decreases, air is drawn into the fuel tank, which mixes with the fuel vapors. During the daylight hours, the temperature of the air may increase causing the pressure of the fuel and/or vapors in the fuel tank to increase. Such an increase in pressure causes fuel leakage or emission of fuel vapors via the fuel delivery system (e.g., a vent). For example, fuel leakage or emission of vapors may occur through a venting system of the fuel system and/or via permeation through various couplings (e.g., valves) of the fuel delivery system components.